import datetime
start = datetime.date(2000, 1, 1)
end = datetime.date(2020, 10, 1)
ans = 0

while start <= end:
    if start.day == 1 or start.weekday() == 0:
        ans += 2
    else:
        ans += 1
    start += datetime.timedelta(days = 1)
print(ans)
